title: Rinne revisited: steel versus aluminum tuning forks.
abstract: OBJECTIVE
  (1) Determine whether tuning fork material (aluminum vs stainless steel) affects Rinne testing in the clinical assessment of conductive hearing loss (CHL). (2) Determine the relative acoustic and mechanical outputs of 512-Hz tuning forks made of aluminum and stainless steel.
  
  
  METHODS
  Prospective, observational.
  
  
  METHODS
  Outpatient otology clinic.
  
  
  METHODS
  Fifty subjects presenting May 2011 to May 2012 with negative or equivocal Rinne in at least 1 ear and same-day audiometry. Rinne test results using aluminum and steel forks were compared and correlated with the audiometric air-bone gap. Bench top measurements using sound-level meter, microphone, and artificial mastoid.
  
  
  RESULTS
  Patients with CHL were more likely to produce a negative Rinne test with a steel fork than with an aluminum fork. Logistic regression revealed that the probability of a negative Rinne reached 50% at a 19 dB air-bone gap for stainless steel versus 27 dB with aluminum. Bench top testing revealed that steel forks demonstrate, in effect, more comparable air and bone conduction efficiencies while aluminum forks have relatively lower bone conduction efficiency.
  
  
  CONCLUSIONS
  We have found that steel tuning forks can detect a lesser air-bone gap compared to aluminum tuning forks. This is substantiated by observations of clear differences in the relative acoustic versus mechanical outputs of steel and aluminum forks, reflecting underlying inevitable differences in acoustic versus mechanical impedances of these devices, and thus efficiency of coupling sound/vibratory energy to the auditory system. These findings have clinical implications for using tuning forks to determine candidacy for stapes surgery.
authors.affiliation: Banner Medical Group, Banner Good Samaritan Medical Center, Phoenix, Arizona, USA.
authors.forename: Cheryl A
authors.initials: CA
authors.lastname: MacKechnie
authors.forename: Jesse J
authors.initials: JJ
authors.lastname: Greenberg
authors.forename: Richard C
authors.initials: RC
authors.lastname: Gerkin
authors.forename: Andrew A
authors.initials: AA
authors.lastname: McCall
authors.forename: Barry E
authors.initials: BE
authors.lastname: Hirsch
authors.forename: John D
authors.initials: JD
authors.lastname: Durrant
authors.forename: Yael
authors.initials: Y
authors.lastname: Raz
mesh_terms: D000328:Adult; D000535:Aluminum; D000554:Ambulatory Care Facilities; D001844:Bone Conduction; D004867:Equipment Design; D005260:Female; D006314:Hearing Loss, Conductive / Q000175:diagnosis*; D006320:Hearing Tests / Q000295:instrumentation* / Q000379:methods; D006801:Humans; D008297:Male; D011446:Prospective Studies; D013232:Steel
chemical_list: D013232:Steel; D000535:Aluminum
keywords: Rinne; conductive hearing loss; otosclerosis; tuning fork